A line production system is a main stream applied in mounting components on a vehicle body, but recently a cell production system comes to be also applied. The line production system is a method whereby components are mounted on the vehicle bodies, which is moving slowly and continuously, by the hands of operators who are waiting on the side of the line. The cell production system is a method whereby component boxes are disposed around a vehicle body and the components taken out from the component boxes are mounted on the vehicle body. So far, various kinds of the cell production system are proposed as disclosed in Patent Literature 1, for example.
A working carriage used in the cell production system disclosed in Patent Literature 1 includes: fixed wheels and free wheels at a lower portion of a support pillar; and a working table is disposed at an upper portion of the support pillar. The working carriage can be manually pushed because the fixed wheels and free wheels are provided.
Therefore, the working carriage is moved by an operator's pushing work along a production line from “START” to “END”. During this time, a component manually taken out by the operator from a component shelf is mounted on a mounting target such as a vehicle body.
The operator stops the working carriage on the side of a desired component shelf and mounts the component, and then moves the working carriage to a next component shelf. Since the working carriage is repeatedly moved and stopped, a stop period of the working carriage is varied depending on operator's skill. As a result, production time control becomes difficult.
According to the technology disclosed in Patent Literature 1, the working carriage is assumed to be a handcart or the like, and therefore, the mounting target loaded on the working carriage is limited to a small-sized article. On the other hand, manufacturing a vehicle body having a length of about 5 meters is also desired. However, in the case where the mounting target is such a large-sized article, the number of components is vastly increased, thereby expanding the production line and elongating an operator's walking distance considerably. In other words, it can be hardly said that the cell production system according to Patent Literature 1 is suitable for the large-sized mounting target such as the vehicle body.
Considering this, desired are a component mounting system and a conveying technology which are suitable for the large-sized mounting target such as the vehicle body and can keep the production time constant.
Additionally, a carriage, a conveyer, etc. may be utilized to convey the workpiece like the vehicle body and the components, but the workpiece and the components can be continuously conveyed by using the conveyer. As a conveyer that conveys the workpiece and components, there is a known conveying technology whereby the workpiece such as the vehicle body is conveyed (see Patent Literature 2, for example.). FIG. 33 is a diagram illustrating the conveyer disclosed in Patent Literature 2.
As illustrated in FIG. 33, a conveyer 200 is used for assembling and conveying the vehicle body. On the conveyer 200, a supporting floor panel 201 having both ends projected arc-shaped and an intermediate floor panel 202 having both ends recessed arc-shaped are arranged such that a projected arc-shaped portion is fitted into a recessed arc-shaped portion.
The intermediate floor panel 202 is connected rotatable around a center shaft of the projected arc-shaped portion of the supporting floor panel 201. At a curve of a vehicle body conveyance passage 203, the recessed arc-shaped portion moves along the projected arc-shaped portion, and there is no gap generated between the supporting floor panel 201 and the intermediate floor panel 202.
In the case where the workpiece is a vehicle body, components are needed to be mounted on the vehicle body. To mount the components on the vehicle body placed on the conveyer 200, the components are needed to be mounted on the moving vehicle body. Therefore, mounting the components becomes easy when the components and the vehicle body are placed together on the conveyer 200. The vehicle body is placed on the conveyer 200 by a lift or the like.
However, since the vehicle body conveyance passage 203 is in a closed state, extra work is necessary to place a plurality of components on the conveyer 200 from a different place, and it is difficult to efficiently supply the components to the conveyance passage 203.
Therefore, demanded is a component conveying system that can efficiently convey and supply components to a conveyance passage by which workpieces are continuously conveyed.